Acceleration proof actuating member



April 28, 1959 J. P. WATSON 2,884,573

ACCELERATION PROOF ACTUATING MEMBER v 4 Sheets-Sheet 1 Filed Sept. 30,1955 IN V EN TOR.

Arm/aways Mun/2, flea/Lee, lmumzz/a 3y UM April 28, 1959 J. P. WATSONACCELERATION PROOF ACTUATING MEMBER 4 Sheets-Sheet 2 Filed Sept. 30,1955 J mes 19 Mao/v INVENTOR.

J. P. WATSON ACCELERATION PROOF ACTUATING MEMBER April 28, 1959 4Sheets-Sheet 3 Filed Sept. 30, 1955 1464750 [NVEN TOR.

5 MM 4 1 [M A ril 28, 1959 4 J. PQWATSON 2,884,573

ACCELERATION PROOF ACTUATING MEMBER Filed Sept. 30, 1955 i 4Sheets-Sheet 4 c/Imms f M975 I N VEN TOR.

United States Patent ACCELERATION PROOF ACTUATIN G MEMBER James P.Watson, Whittier, Calif. Application September 30, 1955, Serial No.537,711 9 Claims. (Cl. 317-195) This invention relates to accelerationproof actuating members, and more particularly to improvedcounterbalance or counterweight means for the armature of anelectromagnet, such as the plunger of a solenoid.

It is an object of this invention to provide counterbalance orcounterweight means for a reciprocably mounted member which does notappreciably increase the overall volume or bulk of the completedapparatus.

It is another object of this invention to provide counterweight meansfor a reciprocably mounted member having such configuration thatstresses and strains in the linkage between the member and itscounterweight are readily absorbed in the counterweight itself, which byits very nature may be made heavy and strong, thus allowing theassociated parts of the apparatus to be only slightly larger than wouldotherwise be required.

It is another object of this invention to provide counterweight meansfor a reciprocable member in which the linkage mechanism between themember and its counterweight is small in both bulk and weight, wherebythe principal weight increase of the apparatus is in the counterweightitself, where it can be employed to full advantage.

It is a further object of this invention to provide such a counterweightmeans as above, which is simple, rugged, and economical to manufacture,assemble, and maintain.

It is a further object of this invention to provide counterweight meansfor a solenoid plunger which may be readily adapted and applied toexisting solenoids and plungers.

It is a further object of this invention to provide counterweight meansfor a solenoid-operated plunger which can be applied with only a veryslight increase in the overall length of the apparatus, and with noincrease in diameter; or alternatively with slight increase in diameterand no increase in length.

It is another object of this invention to provide counterweight meansfor a solenoid-operated plunger which can be applied to a singlesolenoid and plunger.

It is a further object to provide an improved bearing arrangementbetween plunger, standard, and counterweight of the type mentionedabove.

It is a still further object to provide, in an arrangement of the abovetype, means for producing rotation of the plunger with each strokethereof.

It is another object to provide either linear counterbalancing along thelongitudinal axis of a plunger, or rotational counterbalancing aboutsuch an axis.

In accordance with these and other objects which will become apparenthereinafter, preferred forms of the pres ent invention will now bedescribed with reference to the accompanying drawings, wherein:

Fig. l is a perspective view showing one form of the present invention;

Fig. 2 is a fragmentary longitudinal section taken on line 2-2 of Fig.1',

Fig. 3 is a cross section taken on line 3-3 of Fig. l; Fig. 4 is afragmentary section taken online 4-4 of Fig. l;

'ice

Fig. 5 is an elevation partly in section showing a second form of thepresent invention;

Fig. 6 is a view similar to Fig. 5 illustrating the parts in anotherattitude of operation;

Fig. 7 is a cross section taken on line 7-7 of Fig. 6;

Fig. 8 is a top plan view of a third form of the present invention;

Fig. 9 is an elevation partly in section taken on line 9-9 of Fig. 8; r

Fig. 10 is a cross section of another embodiment of the presentinvention illustrating an alternative which may be incorporated into anyof the various forms of the invention.

Fig. 11 is a longitudinal section generally similar to Fig. 2 andillustrating another embodiment of the present invention;

Fig. 12 is a cross section taken on line 12-12 in Fig. 11;

Fig. 13 is a cross section taken on line 13-13 in Fig. 11;

Fig. 14 is a longitudinal section taken on line 14-14 in Fig. 11;

Fig. 15 is a cross section taken on line 15-15 in Fig. 11;

Fig. 16 is a perspective view illustrating another form of the presentinvention, being in particular an alternative way of constructing acertain portion of the embodiment shown in Fig. 11; and

Fig. 17 is a cross section taken on line 17-17 in Fig. 16.

Referring to the drawings, the counterweight means of the presentinvention is shown as applied to a reciprocably mounted member in theform of a plunger 11 actuated by an electromagnet solenoid 12 disposedcoaxially circumjacent the plunger 11 and contained within a case orhousing 13. At least one end of the plunger 11 projects upwardly througha central opening 14 in the top wall of the housing 13, and the upperend of the plunger has a tapped axial bore 16 for receiving any suitablerod or member to be actuated by movement of the plunger 11. The plunger11 is mounted for reciprocation in conventional fashion within thesolenoid coil 12. In the typical case, suitable means are provided forbiasing the plunger 11 upward, and the plunger is drawn downward againstthe bias by electromagnetism whenever the coil 12 is energized.

Proper operation of the solenoid requires that the plunger 11 be movedonly when the coil 12 is energized. Under conditions of severeacceleration occurring longitudinally of the plunger, as for example,under shock or other high acceleration forces, sutficient force on theplunger 11 might be imparted to cause undesired actuation of the partconnected to the plunger 11 in either direction, or to block normaloperation in either direction.

in order to overcome and guard against such undesired actuation of theplunger 11, counterweight means are provided in the form of acounterweight disposed substantially symmetrically coaxially of thereciprocation path of the plunger 11. The counterweight is also mountedfor reciprocation along said path. in the form of the inventionillustrated in Figures 1-4, the counterweight is shown as being oftubular configuration in the form of a tube or cylinder 17.

The counterweight 17 is linked to the plunger 11 through theintermediacy of a standard formed by a sleeve 18 projecting upwardlyfrom the top of the housing 13 coaxially of the plunger 11 and disposedintermediate the plunger 11 and the counterweight 17. Journaled in thesleeve 18 on a substantially tangential shaft 19 is a small gear orpinion 21, which meshes with rack teeth 22 formed on the adjacentinterior surface of the coun- 3 terweight 17 and with rack teeth 23formed on the adjacent surface of the plunger 11. Such engagementbetween pinion 21, and plunger 11 and counterweight 17, respectively,serves to transmit motion of the plunger 11 to the counterweight 17 inopposite directions. Thus, when the plunger 11 is drawn downward, thecounterweight 17 is caused to move upward, and vice versa. By making theweight of plunger 11 equal to that of counterweight 17, a balancedassembly is effected, which is unaffected by acceleration forces thatmight otherwise cause undesired, or block normal, reciprocation of theplunger 11.

If desired, the slot or opening in the sleeve 18 in which the pinion 21is journaled may be strengthened by means of a short radial sleeve 26secured around the slot.

If it is desired that the respective weights of the plunger 11 and thecounterweight 17 should be different, it is only necessary to provide amultiplying linkage between the two, by coupling the teeth 23 to theteeth 22 through two pinions of unequal diameter secured to the shaft19. This expedient may also be used when it is desired tocounterbalance, not only the plunger, but also the part actuatedthereby, provided such part moves parallel to the plunger.

In order to keep the rack teeth 22 and 23 in firm engagement with theteeth of the pinion 21, a roller 24 is journaled in the sleeve 18substantially diametrically of the pinion 21 and bears against theplunger 11 and counterweight 17. Tracks are provided for the roller 24by means of shallow grooves 25 and formed in the respective faces of theplunger 11 and counterweight 17, as shown in Figure 3. If desired, theroller 24 may be provided with teeth, i.e. be a pinion gear, similar to21, engaging corresponding rack teeth in the plunger and counterweight,respectively. Such a second pinion would result in better loaddistribution and would also preclude false operation due to angularacceleration about the axis of shaft 13. This, however, would requireprecise identity between the members 24 and 21 and their respective rackteeth, which would necessitate a very accurate and precise machiningoperation, or an adjustable mounting of at least one set of teeth.Otherwise, there would be danger.

of binding, with consequent undesirable addition of impedance to theready reciprocation of the plunger 11 and counterweight 17.

The key or spline normally required between plunger 11 and solenoid 12is obviated, since pinion 21 and roller 24 serve to prevent turning ofthe plunger 11, and also of the counterweight 17.

Guide means for smooth reciprocation of the plunger 11 and counterweight17 With respect to the standard or sleeve 13 are provided by embossingthe sleeve 18 outwardly, as shown at 27, to provide longitudinal railson which the counterweight 17 may slide; and embossing the sleeveinwardly, as shown at 28, to provide rails on which the plunger 11 mayslide. This serves to keep both the plunger 11 and the counterweight 17centered with respect to the sleeve 18 with consequent minimization ofdanger of binding. Lateral accelerations on the apparatus aretransmitted directly from the counterweight 17 to the sleeve 18 and fromthe plunger 11 to the sleeve 18. The sleeve 18 thus serves to isolatethe counterweight 17 and the plunger 11 from each other with respect tosuch lateral accelerations, which might otherwise cause binding. Sincethe sleeve 13 is fixed with respect to the housing 13, it is in the bestposition to take such lateral accelerations.

As stated, the plunger 11 is adapted to provide a longitudinalreciprocating output through its tapped bore 16. Provision of thelinking pinion 21, however, provides a ready means for also taking offrotary output from the reciprocating movement of the plunger 11. This isdone simply by extending the shaft 19 tangentially outward through alongitudinal slot 31 formed in the counterweight 17. The shaft 19 may becoupled to any suitable output shaft 32, having its own bearings,through a suitable uni-, versal joint 33.

assure M When used in connection with a solenoid 12, as shown, theplunger 11 must, of course, be made of magnetic material. It ispreferred to make the counterweight 17 of non-magnetic material in orderto avoid deleterious magnetic action between the coil 12 andcounterweight 17. While it is possible to make the counterweight 17 of amaterial which is non-conductive as well as non-magnetic, it is oftenpreferable from weight and bulk considerations to make the counterweight17 of a metallic substance which inherently has some conductivity. Inthis instance, it is preferred to provide a longitudinal air gap inorder to eliminate circulating currents which would otherwise introducean undesired transformer action with consequent the same purpose, i.e.,to prevent induced circulating ourrents.

The resilience of the counterweight 17 is employed for the purpose ofachieving a precise fit between the rack teeth 22 and 23 and the pinion21. This is done by making the normal or unstressed size of thecounterweight 17 slightly larger than the final desired dimension. Apair of adjusting screws 36 and 37 are threaded tangentially into thecounterweight 17, the screw 36 passing through the slot 31 above shaft19, and the screw 37 passing through the slot 31 below the shaft. Asshown in Figure 4, the head 34- of each screw bears against thecounterweight 17 at one side of slot 31, and the screw is threaded intothe opposite side. Screwing in of the screw draws the two sides togetheragainst the natural resilience of the cylinder. By proper screwing in ofthe screws 36 and 37, the internal diameter of the counterweight 17 maybe ensmalled just the proper amount to provide a precise fit between theteeth 22-23 and the pinion 21.

As noted above, the weight 17 may also be employed to counterbalance theactuated part as well as the plunger 11. To this end the weight 17 ismade adjustable by providing elongate weights 35 secured in externallongitudinal grooves by screws 40.

Assembly of the counterweight means shown in Figures 1-4 is accomplishedin the following manner. It will be assumed that the case or housing 13is open at the top only, i.e., through the sleeve 18. Grooves 25 and 30-extend the full length of their respective members, and a groove 38forms a continuation of the rack 23 on the plunger. This permits theplunger 11 to be injected into the sleeve 18, and the counterweight 17to be placed over the sleeve 18. The counterweight 17 is placed overthe. standard 18 engaging the pinion 21 and wheel 24, and is droppeddown until it rests against the top of the housing 13. In this position,the pinion 21 engages the upper limits of the rack teeth 22. The screw37 is then screwed in. The plunger 11 is placed into the solenoid 12through the sleeve 18, and the rack teeth 23 are brought into engagementwith the pinion 21. Further insertion of the plunger 11 rotates thepinion 21 and lifts the counterweight 17 away from the housing 13. Thestructure is so dimensioned that when the plunger 11 bottoms within thesolenoid 12, the pinion 21 is in engagement with the upper limits of therack teeth 23 and with the lower limits of the rack teeth 22.

After assembly, the screws 36 and 37 are adjusted to effect properengagement between pinion 21 and racks: 22-23.

Stop means are provided to prevent the counterweight 17 from going sofardown, upon upward movement of the plunger 11, that the piniondisengages from the rack. teeth 23 of the plunger 11. In the presentinstance, such means are shown in the form of a continuous helicalspring or garter spring 41. The spring 41 is placed on the assemblyafter the counterweight 17 has been lifted slight- 1y from the housing'13. The resilience of the'spring' 41;

allows it to be extended outside of the counterweight 17 beyond the stubend of the shaft 19, and dropped down to encircle the bottom portion ofthe standard 18. The normal resilience of the spring then causes it toseat into an arcuate groove 42 formed around the bottom edge of thesleeve 18, as shown in Figure 2. In this position, the spring 41 servesas a stop to prevent disengagement of the teeth, as explainedhereinbefore. The natural resilience or springiness of the spring 41brings about a resilient stop action against the counterweight 17 whichis more desirable than would be a rigid stop.

If desired, the ring 41 may be in the form of a pliant O-ring made ofhomogeneous material such as rubber or neoprene, but because of hightemperature considerations, a metallic garter spring, as describedabove, is preferred.

Other forms of the present invention are illustrated in the followingfigures. In Figure 5, the plunger 11a is linked to the counterweight 17aby means of a pair of arms 21a pivoted intermediate their respectiveends to a standard in the form of a pair of upstanding supports 18asecured to the solenoid case or housing 13a. The upper end of theplunger 11a is bifurcated by the formation of a slot 44 through whichpasses transversely a pin 23a that receives the slotted ends of the arms21a. Slots 46 are formed diametrically in the counterweight 17a toreceive the outer ends of the arms 21a, which are also slotted andsecured to the counterweight by a pair of pins 22a. In this way,downward movement of the plunger 11 is linked with a correspondingupward movement of the counterweight 17a. The slotting of the arms 21apermits the necessary reciprocation while still accommodating arcuatemovement of the ends of the arms 21a.

In the modification shown in Figures 5-7, the counterweight 1711 andplunger 11a may be readily made of different weights simply bypositioning the upright supports 18a at a point which is not midwaybetween the pins 23a and 22a. Thus, if the supports 18a are closer tothe center line of the plunger 11a than to the pins 2211, thecounterweight 17a is made of less weight than the plunger 11a in orderto achieve the necessary counterbalancing action.

The embodiment shown in Figures 57 illustrates that, if desired, thelower end of the plunger 11a may project from the solenoid housing 1312,as shown at 47.

Another embodiment of the present invention is shown in Figures 8 and 9,wherein the counterweight 17b is of somewhat larger diameter than thesolenoid case 13b and encircles the upper end of the case. Thecounterweight 17b is linked to the plunger 11b of the solenoid by threearms 21b spaced equally around the top of the solenoid and pivoted inpairs of supports 18b projecting upward from the top of the case 13b.The inner ends of the links or arms 21b are pivoted to the plunger 11bby screws 23b and the outer ends of the arms 21b are pivoted to thecounterweight 17b by pins 22b pivoted in upstanding pin supports 51extending from the upper edge of the counterweight 17b. As seen inFigure 8, the supports 51 extend inwardly over the edge of the cylinder17b and serve as stops limiting downward movement of 17b.

Like the embodiment shown in Figures 57, that of Figures 8 and 9 mayalso be readily proportioned so as to permit the counterweight 17b to beof lesser or greater weight than the plunger 11b, if desired, simply bysuitable positioning of the supports 18b.

The present invention is equally adaptable to square plungers as toround (i.e. right circular cylinder) plungers 11. Such an embodiment isshown in Figure 10, wherein the plunger lie is shown as being square. Inthis case, the sleeve 180 is likewise square in cross-section as is thetubular counterweight 170.

The embodiment shown in Figure is especially suitable for use with AC.solenoids, the plungers of which are often square or rectangular incross-section.

In Figs. 1l15, there is illustrated still another embodiment of thepresent invention, which follows in general the lines of the embodimentshown in Figs. 1-3, the principal difference being that the bosses 28and 27 forming a bearing surface between the standard and plunger andstandard and counterweight, respectively, have been replaced by elongateball races 54. As shown in Fig. 11 the cylindrical standard 18:23 isdisposed circumjacentthe plunger 11d and within the counterweight 17d.The standard 18d is made in three parts, as shown in Fig. 12, which haveadjacent surfaces 56 disposed obliquely with respect to radii emanatingfrom the center line, or axis 55, of the device. The adjacent surfaces56 are suitably recessed or grooved, to form therebetween elongate,endless ball-races 54 filled with suitable roller members in thispresent instance balls 57.

Each race 54 is comprised of an inside track 28d located between theplunger 11d and the standard 18d; an outside track 27d located betweenthe counterweight 17d and the standard 18d; an upper crossover track 58joining the tracks 27d and 28d at their upper reaches; and a bottomcrossover track 59 joining the tracks 27d and 28d at their bottomreaches.

The oblique disposition of the parting lines or surfaces 56 has thedouble advantage of giving a greater length for the balls 57 to make theturn at 58 and 59, and of displacing the parting line from the radialpressure line which runs through the tracks 27d and 28d. Locating theball races 54 at the parting lines or surfaces 56 permits readymachining of the races into the two adjacent surfaces, as shown in Fig.13, and also simplifies loading of the balls into the races prior toassembly of the three parts forming the standard 18d. The necessity fora loading port with consequent plugging up of the port is thus obviated.

As will be readily appreciated in Fig. 11, as the plunger 11d moves downwithin the standard 18d, the balls 57 in the inside track 28d will berolled downward into the lower crossover 59 and thence upward into theouter track 27d. At the same time, the pressure of the counterweight 17don the balls 57 in the outer track 27:1, causes the outer balls to berolled upward. Thus the fiow of balls in the two tracks agrees with therespective movements of the plunger and counterweight, and except forthe balls in the crossover tracks 58 and 59, all balls are constantly inuse. Thus, there is no idle return race in which the balls must bereturned unused, or deadheading, as it were.

The tracks 27d and 28d of the race 54 are partially formed by providinga shallow, but well defined longitudinal groove in plunger 11d andcounterweight 17d, respectively. This furnishes a rolling keying actionpreventing rotational displacement of both the plunger and counterweightwith respect to the standard 18d. This keying action thus replaces thespline or key provided by the roller 24 in the embodiment shown in Fig.2.

A further feature of the embodiment shown in Figs. 11-15 is the changein position of the return spring for the plunger 11d, from a positionwithin the coil 12, to a position outside of the useful coil field.While not specifically shown in Fig. 2, it will be understood thatinterposed between the plunger 11 and the housing 13, or some otherstationary part of the apparatus, is a return spring biasing the plunger11 outwardly.

As a rule, such return spring is placed in complementary facingrecesses, one recess being formed in the complementary face of a stop oranvil, which is stationarily mounted within the solenoid coil 12 andfixed with respect to the housing 13. Such recessing of thecomplementary faces bewe'en the plunger and anvil, in order toaccommodate the return spring, of necessity decreases the magneticseal-in surface between the two when the plunger is fully pulled in bythe solenoid. Thus the magnetic pull tending to hold the solenoid inclosed position is considerably decreased. Furthermore, the forma= tionof the recesses within the active part of the magnetic field of the coil12 decreases the amount of iron in the 7 plunger 11, with consequentdecrease in the pull-in force. I

In the embodiment shown in Fig. 11, the return spring 61 is placed in anelongate slot 62 formed in the side of the plunger 11a. The bottom ofthe spring 61 rests on a shelf 63 projecting into the slot 62 and formedintegral with the standard 18a. The slot 62 is also employed as aconvenient means for retaining an operating rod 64 secured to the outerend of the plunger 11d. To this end the upper end of the slot 62 isenlarged, as shown at 66, (Fig. 15) to slidably receive a head 67 formedon the bottom end of the operating rod 64 and staked to the plunger 11dat the two corners 70. The undersurface of the head 67 is recessed at 68to receive the upper end of the spring 61, as shown in Fig. 11. The slot62 is continued through to the upper end of the plunger 11d, being atthis point ensmalled properly to receive the rod 64.

The assembly thus described and illustrated in Figs. 11-15 is assembledand held together by means of a bottom retaining ring 71, into which thethree sections of the standard 18d are press-fitted from below, and anupper retaining ring 72 press-fitted, around the upper edge of thestandard 18d, into a groove formed therearound, as shown in Fig. 11.

The assembly is secured as a unit to the solenoid housing 13d by meansof four bolts residing in bolt holes 73, and screwed into the top of thehousing 13d. A shoulder 74 serves to longitudinally position thestandard 18d within the bottom ring 71.

A loose fitting, pliant dust cover 76 is secured in place over theentire assembly, so as to keep dust and other contaminants out of theworking parts; it preferably also covers the bolt holes 73 to completelyseal the unit. The actuating rod 64 projects through the cover 76 so asto be connected to any suitable part to be actuated. The cover 76 is ofsufficient size and pliancy so that when the plunger 11d retracts,pulling the cover downward, the side of the cover may bulge outward toaccommodate the air inside the cover, which would otherwise build up anobstructing pressure.

The embodiment shown in Figs. 11-15 may be completely assembled apartfrom the solenoid proper and may, as a unit, replace a standard plunger.This is accomplished merely by removing the standard plunger from thesolenoid and bolting the assembly shown in Fig. 11 to the top of thehousing 13d, the plunger 11d of the assembly serving to replace thestandard plunger.

In view of the fact that the standard 18a! is made in three parts, theapparatus shown in Fig. 11 may be readily assembled without requiring anextension of the rack groove such as was required at 38 in theembodiment of Fig. 2. The roller 24 being replaced by the ball races 54,the groove 34 of Fig. 2 is, of course, completely eliminated for theentire length of the plunger 11d. As will be readily seen in Fig. 13,the ball races 54 are so positioned that one is diametrically oppositethe pinion 21d, thereby serving to absorb the force exerteddiametrically by the pinion 21d, a function fulfilled by the roller 24in the embodiment of Fig. 2.

When the assembly shown in Fig. '11 is separated from the solenoidproper, the presence of the spring 61 serves as a stop, limitingdownward movement of the plunger 11d, so that the pinion 21d is at alltimes kept in engagement with the rack-teeth on the plunger andcounterweight.

In Figs. 16 and 17, there is illustrated another form of the presentinvention which is essentially a modification .of the form shown inFigs. 11-15.

In this embodiment the standard 18d of Fig. 11 has been replaced by astandard 18e in which the ballraces 5412, instead of being essentiallystraight and parallel to the axis of the standard 18e,are skewed inhelical fashion in. the manner of a thread. Since the balls partiallymate in corresponding helical grooves in the plunger and counterweight,respectively, it follows that each stroke of the plunger causes it torotate as well as to move longitudinally. In similar fashion, thecounterweight is also caused to rotate, and since the counterweight ismoving longitudinally in a direction opposite to that of the plunger,its rotation is likewise opposite and equal to that of the plunger.

Thus, the counterweight tends to counterbalance or offset the rotationalinertia of the plunger as well as the linear inertia. Suchcounterbalancing is not complete, since the counterweight has a greatermoment of inertia and therefore its rotational inertia is greater thanthat of the plunger. Thus, while the magnitudes of the rotationalcounterbalancing are different, they are in opposite directions, andthere is some tendency for counterbalancing rotationally. Completerotational counterbalancing may be achieved by making the rotationalinertia of plunger and counterweight equal, in which case linearcounterbalancing would be incomplete.

The structure shown in Fig. 16 has particular applicability in thoseinstances where it is desired to cause the operated part to rotate aswell as to reciprocate longitudinally. Such might be the case, forexample, with a piston which reciprocates in a cylinder. By inserting anoverrunning or one-way clutch between the plunger and the piston rod,the rod can be caused to rotate in one direction with each stroke, andthus eliminate a tendency for grooves to be worn into the piston andcylinder.

In the embodiment shown in Figs. 16-17, the pinion 21c linking theplunger and counterweight is canted at an angle corresponding to thepitch angle of the rack teeth in plunger and counterweight, which teethare set at an angle corresponding to the helix angle of the races 54e.

It will be understood that in the embodiment of Figs. 16-17 the biasspring cannot be conveniently arranged in the manner shown at 61 in Fig.11, because the helical shape of the races 54a prevents employment ofthe shelf 63. Hence in this embodiment the return spring would be of themore conventional type described hereinbefore.

While the instant invention has been shown and described herein in whatis conceived to be the most practical and preferred embodiments, it isrecognized that departures may be made therefrom within the scope of theinvention, which is therefore not to be limited to the details disclosedherein, but is to be accorded the full scope of the claims.

What is claimed is:

1. counterweight means for a member mounted for reciprocation,comprising: a member mounted for reciprocation along a predeterminedpath, a counterweight dis posed substantially symmetrically coaxially ofsaid path and mounted for reciprocation along said path, a standardhaving a portion disposed between said member and said counterweight,and inflexible linking means pivotally mounted to said standard portion,and engaging said member and said counterweight, for transmitting motionof said member to said counterweight in opposite directions.

2. counterweight means for a member mounted for reciprocation,comprising: a member mounted for reciprocation along a predeterminedpath, a tubular counterweight disposed substantially symmetricallycoaxially of said path and mounted for reciprocation along said path, astandard having a portion disposed between said member and saidcounterweight, and inflexible linking means pivotally mounted to saidstandard portion, and engaging said member and said counterweight, fortransmitting motion of said member to said counterweight in oppositedirections.

3. Counterweight means for a member mounted for reciprocation,comprising: a member mounted for reciprocation along a predeterminedpath, a tubular counter weight open at both ends and disposedsubstantially symmetrically coaxially of said path and mounted forrecip- 9 rocation along said path, said member being adapted to projectthrough each end of said counterweight, a standard having a portiondisposed between said member and said counterweight, inflexible linkingmeans pivotally mounted to said standard portion, and engaging saidmember and said counterweight, for transmitting motion of said member tosaid counterweight in opposite directions.

4. Counterweight means for a member mounted for reciprocation,comprising: a member mounted for reciprocation along a predeterminedpath; a counterweight disposed substantially symmetrically coaliially ofsaid path and mounted for reciprocation along said path; a standardhaving a portion disposed between said member and said counterweight;and a linking pinion pivoted to said standard portion, saidcounterweight and said member being provided with rack teeth engagingsaid pinion for transmitting motion of said member to opposite motion ofsaid counterweight.

5. Counterweight means for a member mounted for reciprocation,comprising: a member mounted for reciprocation along a predeterminedpath; a counterweight disposed substantially symmetrically coaxially ofsaid path and mounted for reciprocation along said path; a standardhaving a portion disposed between said member and said counterweight; alinking pinion pivoted to said standard portion, said counterweight andsaid member being provided with rack teeth engaging said pinion, fortransmitting motion of said member to opposite motion of saidcounterweight, and a wheel pivoted to another portion of said standarddisposed between said member and said counterweight substantiallydiametrically of said pinion, and bearing against said member and saidcounterweight to keep said pinion and rack teeth in firm engagement.

6. counterweight means for a member mounted for reciprocation,comprising: a member mounted for reciprocation along a predeterminedpath; a counterweight disposed substantially symmetrically coaXially ofsaid path and mounted for reciprocation along said path; a standardhaving a portion disposed between said member and said counterweight; alinking pinion pivoted to said standard portion, and having a shaftextending therefrom adapted to provide a rotary output from movement ofsaid memher, said counterweight and said member being provided with rackteeth engaging said pinion for transmitting mo tion of said member toopposite motion of said counterweight, and a wheel pivoted to anotherportion of said standard disposed between said member and saidcounterweight substantially diametrically of said pinion, and

hearing against said member and said counterweight to keep said pinionand rack teeth in firm engagement.

7. counterweight means for a solenoid plunger means mounted forreciprocation, comprising: solenoid plunger means mounted forreciprocation along a predetermined path; solenoid means disposedcoaxially of said plunger means in which said plunger meansreciprocates; counterweight means disposed substantialiy symmetricallycoaxially of said path and mounted for reciprocation along said path; astandard having a portion disposed between said plunger means and saidcounterweight means; and linking means pivotally mounted to saidstandard portion and engaging said plunger means and said counterweightmeans, for transmitting motion of said plunger means to opposite motionof said counterweight means.

8. counterweight means for a member mounted for reciprocation,comprising: a member mounted for reciprocation along a predeterminedpath, a counterweight disposed substantially symmetrically coaxially ofsaid path and mounted for reciprocation along said path, a standardhaving a portion disposed between said member and said counterweight,and rigid linking arm means pivoted at each end respectively, to saidmember and said counterweight and pivoted to said standard portionintermediate said ends for transmitting motion of said member toopposite motion of said counterweight.

9. counterweight means for a plunger comprising a solenoid, a plungerreciprocable within said solenoid and extending therefrom, a standardextending from said solenoid circumjacent said plunger, a cylindricalcounterweight circumjacent said standard and reciprocable coaxially ofsaid plunger, said plunger and counterweight having opposed rack teeth,a pinion journaled on said standard and engaging said rack teeth tocouple said counterweight and said plunger, and removable stop meansspacing said counterweight from said solenoid and preventingdisengagement of said pinion and rack teeth.

References Cited in the file of this patent UNITED STATES PATENTS134,698 Otis Jan. 7, 1873 782,347 Lidback Feb. 14, 1905 817,675 ShipmanApr. 10, 1906 890,389 Wilson June 10, 1908 1,624,702 Whipple Apr. 12,1927 1,964,319 Gorton June 26, 1934 2,513,934 Hall July 4, 19502,628,135 Magee Feb. 10, 1953 2,655,415 Briney Oct. 13, 1953 FOREIGNPATENTS 534,114 France Dec. 30, 1921 UNITED STATES P TENT OFFICECERTIFICATE OF CORRECTION Patent No. 2,884,573 7' April 9 James P.Watson I It is hereby certified that error apfiears in the abovenumbered paten requiring correction and that the said Letters Patentshould rear? as corrected below.

In the drawings, Sheet 1, Fig. 1, change '29", three occurrences, to 2'7Fig. 2, change the reference line from numeral 23 to indicate the rackteeth on plunger 11; Fig. 4, change "36" to 3'7 Sheet 3, Fig. ll, addnumeral 62' and reference line to indicate slot in plunger lld foraccommodating spring 61; Fig. 15, add numeral "66" to indicate crossslot in plunger lld to accommodate part 67; in the printedspecification, column 2-, line 22, for "Fig. 11'' read Figs. 11 and 13column 3, line 29, for "25 and 30" read 30 and 25 line 30, for "faces"read surfaces column 5, line 12, for "ring" read spring column '7, line54, for the numeral "34" read 30 Signed and sealed this 3rd day of May1960.

(SEAL) Attest:

KARL H. .AXLINE ROBERT C WATSON Attesting Officer Commissioner ofPatents UNITED STATES 'PATFNT OFFICE CERTIFICATE OF CORRECTION PatentNo. 2,884,573 U A1551 195-9 James P. Watson I i It is. hereby certifiedthat error appears in the above numbered paten requiring correction andthat the said Letters Patent should rea as corrected below.

In the drawings, Sheet 1, Fig. 1, change "29", three occurrences, to

-- 2'7 Fig. 2, change the reference line from numeral 23 to indicate therack teeth on plunger ll; Fig. 4, change "36" to 3'7 Sheet 3, Fig. ll,add numeral 62' and reference line to indicate slot in plunger lld foraccommodating spring 61; Fig. 15, add numeral "66" to indicate crossslot in plunger lld to accommodate part 67; in the printedspecification, column 2-, line 22, for "Fig. 11" read Figs. 11 and 13column 3, line 29, for 25 and 30" read 30 and 25 line 30, for "faces"read surfaces column 5, line 12, for "ring" read spring column '7, line54, for the numeral "34" read 3O Signed and sealed this 3rd day of May1960.

(SEAL) At test KARL H. ,AICLINE ROBERT C WATSON Attesting OfficerCommissioner of Patents

